1. Field of the Invention
The present invention relates to irrigation systems and methods. More specifically, the present invention relates to an apparatus and method for controlling water flow in an irrigation system.
2. Description of Related Art Irrigation not only permits foodstuffs to be grown, but also enables the cultivation of attractive plant life that otherwise would not have sufficient water to thrive. Many households now utilize sprinkler systems to provide irrigation in a comparatively uniform and trouble-free manner.
Often, a control unit such as a timer is used to regularly initiate operation of the sprinkler system to automatically provide the desired distribution of irrigation water. The timer is electrically connected to a plurality of electrically operated valves, each of which is able to permit water to flow into a corresponding zone of the sprinkler system. The valves must be individually activated so that the entire pressure and flow rate available will be focused on each zone, in turn.
Many known valves utilize an electrically driven actuator such as a solenoid. In many configurations, the solenoid has a plunger that can be extended to plug a hole of a diaphragm, and to press the diaphragm toward an outlet opening. Upon extension, the plunger keeps the diaphragm closed to block water passage through the valve. Upon retraction, the plunger permits water to flow through the hole in the diaphragm and through the outlet opening, thereby reducing water pressure between the diaphragm and the solenoid to induce the diaphragm to move away from the outlet opening, thereby opening the valve. Often, the solenoid is a xe2x80x9clatchingxe2x80x9d or xe2x80x9cbi-stablexe2x80x9d solenoid, which means that the plunger remains in the extended or retracted positions without requiring continuous power.
Unfortunately, such valves have a number of disadvantages arising from the fact that the solenoid is continuously exposed to the irrigation water. For example, exposure to water requires the use of corrosion resistant materials, such as stainless steels, for the plunger and the interior chamber of the solenoid. These materials add significantly to the cost of the solenoid. A significant danger of corrosion of the chamber or plunger may yet remain, particularly if the irrigation water is oxygenated or polluted.
Hence, it would be an advancement in the art to provide a valving apparatus and method that provides a high degree of corrosion resistance without requiring the use of a solenoid made from corrosion resistant materials. It would be a further advancement in the art to provide a sprinkler valve that is simple, inexpensive, easy to assemble, and reliable in operation.
The apparatus of the present invention has been developed in response to the present state of the art, and in particular, in response to the problems and needs in the art that have not yet been fully solved by currently available sprinkler valving systems and methods. Thus, it is an overall objective of the present invention to provide sprinkler valves and associated methods that remedy the shortcomings of the prior art.
To achieve the foregoing objective, and in accordance with the invention as embodied and broadly described herein in the preferred embodiment, an irrigation system is used to irrigate an area. The irrigation system has a valving system designed to control flows of an irrigation liquid, such as water, to a plurality of water distribution units such as sprinklers. The sprinklers receive water from a plurality of distribution conduits, each of which is in communication with a valve assembly. Each valve assembly has a fluid transfer portion and an actuator portion designed to actuate elements within the valve housing to move the valve assembly between an open configuration and a closed configuration.
Each valve assembly also has a pair of wires that conveys a valve activation signal to the actuator to move the valve assembly between the open and closed configurations. The valve assemblies may be connected to a feeder conduit to form a manifold that receives water from a main line. The manifold may be disposed underground, within a manifold box covered by a lid. Alternatively, the manifold may be attached to an above-ground spigot for use in a hose bib irrigation system. Control unit wires extend from the valve wires to a control unit, such as a timer.
Each valve assembly includes an inlet conduit and an outlet conduit, both of which are connected to a valve. The valve has a conduit junction that permits water to pass between the inlet and outlet conduits when the valve is in an open configuration. Water is unable to pass through the conduit junction when the valve is in the closed configuration. The conduit junction has a primary outflow passageway and a secondary outflow passageway.
The valve also includes a first diaphragm, an interior divider, a second diaphragm, an interior retainer, and a solenoid. The first diaphragm is sandwiched between the conduit junction and the interior divider such that the first diaphragm is flexible to block or unblock the primary outflow passageway. A first chamber is defined by the first diaphragm and the interior divider. The first diaphragm has a hole designed to permit irrigation water to flow into the first chamber at a limited flow rate.
The interior divider has an orifice designed to permit irrigation water to leave the first chamber at a flow rate greater than that of entry through the hole of the first diaphragm when the orifice is open. The second diaphragm is sandwiched between the interior divider and the interior retainer such that the second diaphragm is flexible to block or unblock the orifice. A second chamber is defined by the interior divider and the second diaphragm.
The solenoid is disposed on the opposite side of the interior retainer from the second diaphragm. The solenoid has a magnetically actuatable plunger with a post positioned to extend through an aperture of the interior retainer to reach the second diaphragm. Thus, the magnetically actuatable plunger can be moved to press against the second diaphragm, thereby causing the second diaphragm to abut the orifice of the interior divider to block fluid communication between the first and second chambers.
When the second diaphragm abuts the orifice of the interior divider, pressure within the first chamber will tend to equalize with that of the inlet conduit. As a result, the first diaphragm is pressed against the primary outflow passageway of the conduit junction. The valve is then in the closed configuration.
In order to open the valve, the plunger is withdrawn by the solenoid. Thus, the second diaphragm is permitted to withdraw from the orifice, thereby unblocking the orifice to permit fluid communication between the two chambers. Water pressure within the first chamber is reduced as water moves from the first chamber to the second chamber. The interior divider has an outflow passageway in communication with the secondary outflow passageway of the conduit junction. Thus, water vents relatively freely from the first chamber, thereby reducing its pressure.
In response to reduction of water pressure within the first chamber, the first diaphragm deflects to the open position. Water is then able to flow through the primary outflow conduit of the conduit junction to reach the outlet conduit, and subsequently, the corresponding distribution conduit and water distribution unit(s) The first diaphragm remains open until the second diaphragm is again actuated to close the orifice Throughout the process, the second diaphragm acts as a seal to isolate the solenoid from irrigation water.
According to one embodiment, the second diaphragm has a peripheral ring that also abuts the interior divider, around the orifice. The peripheral ring is drawn into sealing engagement with the interior divider if the outlet conduit is at a pressure lower than that of the solenoid interior. This isolates the orifice from the potential vacuum to ensure that the second diaphragm is able to withdraw from the orifice to trigger movement of the first diaphragm to open the valve.
Such a valve assembly may be easily manufactured through the use of a number of steps. According to one method, the inlet conduit, outlet conduit, and conduit junction are injection molded or otherwise unitarily formed. The first diaphragm is inserted into engagement with the conduit junction. The interior divider is then positioned such that the first diaphragm is sandwiched between the interior divider and the conduit junction The second diaphragm is positioned against the interior divider. The interior retainer is then disposed such that the second diaphragm is sandwiched between the interior divider and the interior retainer.
The solenoid is then installed in such a manner that the magnetically actuatable plunger is able to press against the second diaphragm when the valve is to be moved to the closed configuration. A cap is attached to the conduit junction in such a manner that the cap keeps the first diaphragm, the interior divider, the second diaphragm, the interior retainer, and the solenoid in place. The solenoid is disposed outside the interior retainer The aperture of the interior retainer is isolated from water by the second diaphragm; hence, the solenoid is also isolated from the irrigation water.
Through the use of the apparatus and method of the invention, valve solenoids may be substantially isolated from the irrigation water Thus, irrigation valves may be more easily and economically produced Furthermore, such irrigation valves may operate more reliably, with a smaller danger of failure due to corrosion These and other features and advantages of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter.